Rotary cutting tools having holders and replaceable cutting inserts clamped therein by a clamping screw are known. When using such a rotary cutting tool at high speeds, however, stability problems arise due to a great magnitude of centrifugal forces created by the high rotational speed at which the rotary cutting tool operates. Moreover, the centrifugal force can cause shearing of the clamping screw. Due to these problems, use of conventional clamping methods is limited and it is unsatisfactory to rely exclusively upon a clamping screw to releasably secure the cutting insert to the holder or to a cassette. Employing external clamps only aggravates the problem, since the added mass of the clamps creates even greater centrifugal forces, making the stability problems even worse. Consequently, tools for high-speed machining require creation of an interlocking connection in order to absorb the greater part of the centrifugal force and decrease the level of stress on the mounting means.
Known interlocking connections are, for example, tongue and groove connections in which the supporting surface of the cutting insert features a rectangular tongue which is engaged with a corresponding groove of the receiving surface of the main body of the tool. Such a clamping arrangement is shown in U.S. Pat. No. 5,944,456; U.S. Pat. No. 6,203,251; U.S. Pat. No. 5,924,826 or WO 95/29026.
However, this type of construction leads to very high levels of stress on the main body of the tool, especially, in the base region of the groove due to the notch effect.
Mating serrated surfaces are another known clamping arrangement. DE Patent Application No. 35 33 125 A; U.S. Pat. No. 6,244,790; U.S. Pat. No. 6,102,630 or US 2004/0101371 disclose mating supporting surfaces of an indexable insert and a receiving surface of a tool featuring serrations in mutual engagement.
However, such a clamping arrangement may create over-constrained clamping, which may cause equivocal positioning of the indexable insert in the tool body.
U.S. Pat. No. 6,196,769 discloses a rotary cutting tool for high-speed machining having a cutting insert interchangeably mounted in a tool body. At least parts of a supporting surface of the cutting insert and of a receiving surface of the tool body are of a V-shaped configuration and are engaged with each other, when viewed in a cross section perpendicular to an axis of rotation of the rotary cutting tool. In order to radially support the cutting insert, a bearing surface on the tool body is arranged in such a way that a mounted cutting insert is tilted such that the supporting surface of the tool body and the receiving surface of the cutting insert come into mutual contact at only two points.